A gimbaled inertial measurement unit is used for vehicle navigation and object tracking. The gimbaled inertial measurement unit includes multiple gimbals that each rotate along a single axis to position sensors along the vehicle's path. By using multiple gimbals, such as three or four gimbals, a vehicle's inertia can be monitored in multiple axes by the sensors and used for inertial navigation. Inertial navigation continuously calculates by dead reckoning the position, the orientation, and the velocity of a moving object without the need for external reference. Dead reckoning (or deductive reckoning) involves calculating the vehicle's current position by using a previously determined position and advancing that position based upon estimated speeds and headings.
Gimbaled inertial measurement units include additional sensors, such as resolvers, to determine a position of a motor that drives each of the multiple gimbals and positions the sensors that track the vehicle's inertia. A resolver is an analog sensor that is used to determine rotational position, such as an angle. The resolver receives an excitation signal and generates analog output signals which are converted to digital samples. The digital samples are used to determine a position of the motor and the gimbal. The position outputs determined from the output analog signals may lose precision during the conversion from analog to digital or from processing the digital samples into the angle outputs. Additionally, interference from current switching during operating the gimbal motors can add noise and errors. Reduced precision and errors accumulate over time in inertial navigation and can lead to incorrect data or navigation.
Complicated discrete solutions are often used to increase precision or bandwidth of the gimbaled inertial measurement units needed for mission or design requirements. However, these solutions do not generally provide increased precision and increased bandwidth simultaneously. Additionally, these solutions add complexity, cost, weight, and volume to vehicle design. In the context of flying vehicles (aircraft, spacecraft, etc.), weight and volume greatly increase cost and reduce performance.